DDS (Document Distribution Service) being blocked specifically on port 7789

[laffeg]

Hi

upgraded 60F to 7.4.9 and our client's 3rd party provider is saying all devices are getting DDS blocked

was using Web filter and SSL inspection on the outbound firewall policy

still same with them both turned off

I can't see it being blocked in forward traffic logs

do I need to go up to 7.6  or is there another fix ?

any help appreciated

Graeme

[AEK]

Hi Graeme

You may have hit the below known issue. Try reboot and see if it helps.

1035490

The firewall policy works with proxy-based inspection mode on FortiGate models with 2GB RAM after an upgrade. Workaround: After an upgrade, reboot the FortiGate.

In case it doesn't help, I heard (but nothing official) about some possible mtu/mss related issues following upgrade to 7.4.9.

This tech tip shows how to diagnose the issue and eventually how to fix it.

https://community.fortinet.com/t5/FortiGate/Technical-Tip-Setting-TCP-MSS-value/ta-p/194518

Hope it helps

[laffeg]

reboot didn't help - realise now that the issue started before I did the firmware update

So question why would a Fortigate suddenly start blocking port 7789 and not show anything in the logs ?

[AEK]

Did the shared tech tip help?